Heat pipes are known which have long heat transport distances that result from having the evaporator surface at one end of the heat pipe and the condenser surface at the opposite end. These heat pipes usually have relatively low heat transport capabilities as there are high viscous liquid pressure losses associated with the arterial liquid flow means. This has resulted in the fabrication of larger structures to handle high heat loads. Also, the prior art variable conductance heat pipes have had limited heat capacity and have been unable to handle high heat loads without burnout. A variable conductance heat pipe is mentioned by Bienert et al, AIAA Progress in Astronautics and Aeronautics: Fundamentals of Spacecraft Thermal Design, Vol. 29., Lucas, MIT Press Cambridge, Mass (1972) pp 463-485).
It has now been found that a high performance variable conductance heat pipe may be made by constructing a transverse heat pipe that is provided with a baffle which causes vaporized liquid to flow in a longitudinal direction and liquid to flow in a transverse direction and a non-condensible gas that permits the operating surface area of the condenser region of the heat pipe to vary with the heat load.
Therefore, it is an object of this invention to provide a variable conductance heat pipe that has the capacity to handle higher heat loads.
It is also an object of this invention to provide a variable conductance heat pipe that is constructed without an artery and to thereby eliminate the priming problems, the bubbles and the depriming problems which are found in arterial wick heat pipes.
It is also an object of this invention to provide a variable conductance heat pipe having a more compact structure than prior art variable conductance heat pipes.